As CMOS devices scaling down in nowadays integrated circuits, the impact of layout-dependent effects (LDEs) to circuit performances becomes to be significant. This paper mainly focuses on LDE-aware analog circuit synthesis. Our circuit synthesis follows an optimization framework of transistor sizing based on geometric programming (GP) in which analog circuit performances are formulated in terms of monomials and posynomials. Providing GP models for the LDEs such as the shallow trench isolation (STI) stress and the well proximity effect (WPE), we can generate layout constraints related to LDEs during the circuit synthesis. Applying our circuit synthesis to a typical two-stage op-amp, we showed that the resultant circuit, which generated by GP with circuit performance and layout constraints, satisfied all the specifications with the verification of HSPICE simulation based on the BSIM model with LDE options.

A four-quadrant-input linear transconductor generating a product or a product sum current is proposed. The proposed circuit eliminates the influence of channel length modulation and expands a dynamic input voltage range. As an application of the proposed circuit, the four-quadrant analog multiplier is designed. The four-quadrant analog multiplier consists of the proposed circuit, an input circuit and a class AB current buffer. HSPICE simulation results with 0.35 µm n-well single CMOS process parameter are shown in order to evaluate the proposed circuit.

A linear voltage-to-current convertor without current mirror circuit is proposed for low distortion applications employing short channel MOSFET's. Twin current sources and current sinks pair of MOSFET's having the same drain-source voltage are employed for a substitute of the current mirror circuits, in order to eliminate the channel length modulation factor of the short channel MOSFET's. HSPICE simulation is shown in order to evaluate the proposed circuits. As an application, a low distortion OTA is realized by employing the proposed linear voltage-to-current convertor with short channel MOSFET's.